Kris typed:
I have a 50 gallon tank with angels, otto's, apistogramma cacatoides,
a figure eight and bleeding heart tetra's.

Interesting mix, especially with a puffer, apistos, angels, that mix usually
wouldn't work, but YMMV, so let's keep going...

since 2-3 months, every two weeks one fish dies. I've lost 1 Boekhlei,
2 angelfish and one apistograma that way. They have no symptoms
untill their last hour. Then they sink to the bottom, start havy
breathing ans then they die.
They eat well. I've noticed light coloured stool with a bit of a slimy
aspect. I thought about hexamita but then again, they don't have hole
in the head symptoms and they did not lost weight and eat well, and
they are brightky coloured.
Can hexamita be the reason, killing them one by one without others
symptoms?

Hexamita is defined as Hole in the Head, disease, YOU'D see it...read it
here
http://www.thetropicaltank.co.uk/hdhith.htm

or
http://www.google.com/search?hl=en&i...=Google+Search

Should I give them something like hexamita(R) from 'Esha
Labs'? I don't like to do it because Apistogramma's dont't love
medication... But if that's what I got to do...

My guess would be that maybe poor water quality, combined with an unusual
mix of fish, could possible cause potentially life threatning stress upon
some inhabitants, and yes, stress kills.

While you're here, post some parameters of your tank, pH, gH, kH, cleaning
regimine, and anything else you add to your tank, and I'll bet someone here
can pinpoint what's happening, or where it is going wrong...

btw, it never hurts to do water changes when things don't look right...

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